Tubular element for the formation of bags for the vacuum-packing of products

Abstract: The present invention pertains to a tubular element for the formation of bags for the vacuum-packing of products, consisting of an inner layer or film (14) having thread-like elements (15), which extend along the length of the tubular element and are intended to be relief on at least on inner surface of the resulting bag and to define among themselves channels (16) for the evacuation, by suction, of air from the bag at the time of using the bag for the vacuum-packing of a product.

Description: The present invention pertains to packing materials, and more specifically, to an element for the formation of bags that are impermeable, heat-sealable and intended for the vacuum-packing of perishable products. Packing materials in the shape of tubular elements, which are sealed in the longitudinal direction by means of bonding and are capable of being shaped into bags for the above-mentioned use, have already been proposed. According to a known embodiment, the wall of the tubular element consists of at least two overlapping elements which are made of different materials, specifically an outer layer or film made of a material that is impermeable to gases and an inner layer or film made of a thermoplastic, heat-sealable material. The two layers are intimately overlapped, and at least the inner layer has an embossing or a network of channels, which promote the outlet of air at the time the bag is used for vacuum-packing. Therefore, the network of channels is obtained on the inner, heat-sealable layer of the element. One bag of this type has been disclosed, for example, in EP-A-0 216 327 (which corresponds to US-A-4 576 422). However, in these documents bags are described having interconnecting air channels separated by protrusions or "islands", obtained by embossing, i.e. by deformation of the inner layer of the receptacle or by means of variations in the thickness of a layer of material. A production process of this type of sheets is complex, relatively unprofitable and difficult to use in industry. The present product can be obtained by direct or indirect extrusion methods simplifying its production. On the other hand, the purpose of the present invention is to provide a packing material with walls which are formed by two or more layers or films made of different plastic materials, and in which, with the impermeability and heat-sealability remaining constant, the channels for the discharge of air are defined by thread-like elements which are applied on at least one inner surface of the manufactured article. Thus, the embossing is eliminated, causing the bags for the vacuum-packing to be more simply and economically produced and to have reliable use. Therefore, the present invention is focused on a tubular element for the formation of bags for the vacuum-packing of products in accordance with claim 1. Details of the present invention will become more evident from the description below with reference to the attached drawings, in which: Figure 1 shows in perspective view a cut section of a tubular element intended to form a bag for the vacuum-packing of products; Figure 2 shows an enlarged detail of the cut section in Figure 1; and Figure 3 shows a partial view of the inner surface of the tubular element with channels defined by thread-like elements in relief. In general terms, the tubular element under examination, indicated as a whole by 10, can be formed by one or by two sheets or bands and sealed in the longitudinal direction, by means of bonding, along one side or two sides, as indicated by 11. In the example shown, the tubular element consists of two sheets or bands 12, 12', sealed along two opposing sides. The tubular element is then cut to the desired length, sealed in the cross-sectional direction, by means of bonding, at one of its ends to form a bag and, at the time of use, at the opposite end, after having arranged the product to be packed and having created the vacuum. The sheet or sheets, which contribute to the formation of the tubular element, and therefore also the formation of the resulting bag, is or are formed by an outer layer or film 13, which is made of a material, such as nylon or polyester, is airtight, that is, impermeable to gases, such as polyethylene or polythene, and is heat-sealable. The two layers or films 13, 14 are overlapped and intimately connected. In accordance with the present invention, thread-like elements 15, which extend along the length of the sheet proper, are applied on the inner surface of at least one of the sheets 12, 12', for example, 12 in the drawing, and more precisely on the inner layer or film 14 made of polyethylene or polythene. The thread-like elements 15 are applied at least on the sheet 12,preferably before assembling the two sheets 12, 12' in order to form the tubular element and subsequently the bags. The thread-like elements 15 are preferably made of the same material, polyethylene or polythene, forming the inner layer or film 14, and they are inserted in a suitable manner, yet so as to be in relief on the inner surface of the tubular element 10 and therefore of the resulting bag. Such an embodiment is illustrated in the drawings, from which it can be ascertained (Figures 1 and 2) how the thread-like elements define, on the inside of the tubular element and consequently of the bag, longitudinal channels 16 which permit a complete evacuation of the air, by suction, from the bag at the time of using the bag for the vacuum-packing of products with equipment which is known per se and does not merit particular attention here.

Claims: Tubular element (10) for the formation of bags for the vacuum-packing of products, said element being formed by at least one starting sheet (12, 12'), which consists of at least one outer layer or film (13), made of a plastic material that is impermeable to gases, and of an inner layer or film (14) made of a thermoplastic, heat-sealable material, said two outer and inner layers being intimately connected, the inner surface of at least one of said inner layers (14) comprising evacuation channels (16), characterized in that parallel thermoplastic, heat-sealable thread-like elements (15) are applied along a length of said tubular element defining bulges extending away from said inner surface (14), and being spaced apart to define said channels. Tubular element in accordance with claim 1, in which said thread-like elements (15) are inserted on said inner layer or film (14) and are arranged so as to fill up at least one inner surface of the resulting bag and to extend along the depth of said bag. Tubular element in accordance with claims 1 and 2, in which the outer layer of film (13) of the starting sheet or sheets (12, 12') is made of nylon or polyester, in which the inner layer or film (14) of said starting sheet (12, 12') is made of polyethylene or polythene, and in which said thread-like elements (15), which define the channels (16), are made of the same material as said inner layer or film (14).

Inventors: ABATE LUIGI, ABATE, LUIGI
Applicants: FLAEM NUOVA SPA, FLAEM NUOVA S.P.A.
Application year: 1994
Main classification: B65D81
IPC codes: B65D81, B65D3, B65D30, B32B3